JPS58121099A - Plosive detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plosive sound detection device for detecting plosive sounds.

Conventionally, there is no known method for detecting plosive sounds reliably, easily, and in real time from the characteristics of sounds picked up by a microphone in the usual way.

The present invention provides a plosive sound detection device that detects plosive sounds simply and in real time.

Experiments have revealed that it is possible to detect the oral airflow that accompanies speech, and to reliably detect plosive sounds from the oral airflow. However, when a plosive sound is in the middle of a continuous utterance, apart from the oral airflow corresponding to the plosive sound, an oral airflow similar to that for a plosive sound may occur at the end of the vowel, and only the plosive sound It has become clear that this hinders the specific detection of

Accordingly, another object of the present invention is to provide a plosive sound detection device that reliably detects oral airflow corresponding to a plosive sound even when the plosive sound is in the middle of a continuous utterance. The present invention will be described in detail below using Examples.

The plosive sound detection device according to the present invention basically includes a flow velocity detector 1 for detecting oral airflow as shown in FIG. It is comprised of a signal processing circuit 3 that controls the output signal of the detector 1 and extracts only the oral airflow of plosive sounds. The flow velocity detector 1 detects the flow velocity of the oral airflow during speech, changes in flow velocity (acceleration), etc., and is composed of, for example, a hot wire type wind velocity detector, a microphone with a windshield removed, or the like. Further, the flow velocity detector 1 is placed in front of the speaker's mouth at a position where the oral airflow associated with speech can be detected. The voice detector 2 detects the voice when speaking, and is composed of, for example, a close-talk type microphone. Similarly, the voice detector 2 is also placed at a position near the speaker's mouth where the voice can be detected. The signal processing circuit 3 controls the output signal of the flow velocity detector 1 using the output signal of the voice detector 2. For example, the signal processing circuit 3 controls the output signal of the flow velocity detector 1 for a certain period before and after the final vowel of the voice signal. configured to control.

The signal processing circuit 3 includes a detection circuit 31 that detects the output of the audio detector 2 at a certain level or higher, a control circuit 34, and a detection circuit 31.
Monostaple multipipe rake (MM) 32, R-8 for generating a control signal for the control circuit 34 from the output of
It is composed of a flip-flop (FF) 33.

FIG. 2 shows signal waveforms at various parts to explain the operation of the embodiment shown in FIG. 1. Waveform A shows a typical example of a voice signal when a plosive sound detected by the voice detector 2 is in a word of continuous speech.

The waveform mouth shows a typical example of a mouth airflow signal when the above-mentioned plosive sound detected by the flow velocity detector 1 is in a word of continuous speech. Here, an example is shown in which ``l aPal'' is uttered.

According to experiments, when a plosive sound is present in a word of continuous speech, here, when uttering 1aPal, the mouth airflow signal mouth is a plosive sound I.
A mouth airflow signal (hereinafter referred to as rupture orifice airflow signal α) having a pulse-like waveform with a unique steep rise corresponding to P+, and a mouth airflow signal similar to the waveform of the rupture orifice airflow signal a (hereinafter referred to as rupture orifice airflow signal α) An airflow signal β) is generated. The mouth closure airflow signal β occurs at the end of the vowel 1al preceding the plosive, which corresponds to a time just before the lip closure point.

After that, there is a closure period of the plosive sound IP+, and within this closure period, the intraoral pressure rises, and almost at the same time as the opening point, the plosive mouth airflow signal α
occurs. The closed mouth airflow signal β differs depending on the speaker, speech method, and type of plosive, but its generation period is 100
A few dozen (
msec).

Therefore, when a plosive sound is present in a word of continuous speech, it is difficult to accurately detect only the plosive sound using the oral airflow signal alone.

According to the plosive sound detection device shown in FIG. 1, the signal processing circuit can detect that the phase relationship between the speech signal A and the closure airflow signal β is such that the closure airflow signal β is generated at the end of the vowel of the speech signal A. By suppressing the mouth airflow signal for the defined period before and after the end of the vowel of the voice by 3, only the mouth airflow of the plosive is extracted as shown in FIG. 2C.

For this reason, in the signal processing circuit 3, the detection circuit 31
As a result, a period in which the output threshold of the sound detector 2 is also detected is detected, and a detection pulse indicating this period is obtained. The output of the detection pulse is added to FF5s and MMA・2,
MMa2 is the closed mouth airflow signal β from the end of the detection pulse.
A pulse with a pulse width tl that includes the generation point of is generated.

FF33 has a set input for the output of the detection circuit 31, and MMA
The inverted output Q of MMa2 is reset inputted, and a control signal 2 whose pulse period is from the start of the detection pulse indicating the voice section to the end of the output of MMa2 is generated. suppresses the output port. As a result, only the oral airflow component corresponding to a plosive sound, as shown in FIG. 3E, can be detected as the output of the signal processing circuit 3.

FIGS. 4 and 6 show other embodiments of the plosive sound detection device according to the present invention. The configuration of FIG. 4 is the same as that of FIG. 1 except for the signal processing circuit 3. The signal processing circuit 3 includes a delay circuit 41 that delays the output of the audio detector 2 by t2, an envelope detection circuit 42, an integration circuit 43, and a control circuit 44.

In this embodiment, the output signal of the audio detector 2 is obtained as a signal delayed by t2 by the delay circuit 41 using a charge transfer element such as a CCD1BBD. The positive polarity portion of the delayed audio output is detected by an envelope detection circuit 42 and integrated by an integration circuit 43, thereby obtaining a signal representing the power of the audio detection signal, as shown in FIG. A signal representing this power is sent to the control circuit 44 as a control signal.
Similarly to FIG. 1, the signal output from the flow velocity detector 1 is suppressed at a level above a predetermined threshold of the signal. Here, the number of stages and clock frequency of the charge transfer elements constituting the delay circuit 41 are such that the delayed audio detection output completely includes the above-mentioned closed mouth airflow signal β, but does not include the bursting mouth airflow signal α. It is set to give time.

Further, the control circuit 44 includes a gain control amplifier whose gain decreases as the control signal increases.

In this configuration, the envelope detection circuit 42 and the integration circuit 43 obtain a signal T representing the power to the delayed audio signal, and the magnitude of the power is l-
It is large at 1 and zero at IPI. Therefore, the control circuit 44 operates to suppress the output from the flow velocity detector 1 in the case of la+ with a large power signal level, and to allow it to pass through in the case of IPI. As a result, the aforementioned closed mouth airflow signal β is removed as an output of the control circuit 44, and only the mouth airflow corresponding to the plosive sound can be detected.

As is clear from the above description, according to the present invention, even when a plosive sound is present in a word of continuous speech, only the oral airflow corresponding to the plosive sound can be reliably detected. Furthermore, the configuration of the plosive sound detection device is simple, and detection can be performed in real time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of a plosive detection device according to the present invention, FIGS. 2 and 3 are diagrams showing waveforms of each part of FIG. 1, and FIG. 4 is a block diagram showing a plosive sound detection device according to the present invention. A block diagram showing the configuration of another embodiment of the detection device, FIG. 5 is a diagram showing waveforms of each part in FIG. 4. 1...Flow velocity detector, 2...Audio detector, 3...Signal processing circuit, 31...Detection circuit, 32 Fist...Fist... Monostable multi-pie Bray 611J11@ΦR-S flip-flop, 34...
...control circuit. 1st composition 4rl! JG Chokyu Exhibition Ship Rei

Claims (2)

[Claims] (1) A flow velocity detection means for detecting oral airflow, a sound detection means for detecting sound, and an output signal of the sound detection means controls the output signal of the flow velocity detection means to extract only the oral airflow of plosive sounds. A plosive sound detection device comprising a processing means. (2) In claim 1, the processing means includes a delay section that delays the output signal of the audio detection means, an amplitude detection section that detects the power of the output signal of the delay section, and an output of the amplitude detection section. A plosive sound detection device comprising a suppressor that reduces the output signal of the flow velocity detection means when the magnitude of the signal becomes large.